Elimination of black specks from textile yarn



Patented Aug. 10, 1954 ELIMINATIONOF BLACK SPECKS FROM TEXTILE YARN Robert Ellis Clark, Midlothian, E. I. du Pont de Nemours &

Va., assignor to Company, Wilmington, Del., a corporation of Delaware No Drawing. Application March 20, 1951, Serial No. 216,676

6 Claims. 1

This invention relates to a method of eliminating black specks and stains from viscose rayon yarn.

The formation of dark specks on viscose rayon yarn has led to a great deal of study and research to develop a speck-free yarn. While it has been understood that the specks are caused by the presence of lead in the spinning bath, which is picked up by the yarn and converted to dark specks when the lead reacts with sulfide ions in the desulfuring step of the process, many proposals to alleviate this condition have proven ineffective or uneconomical for commercial use. The elimination of lead from the bath is quite impossible in view of the large amounts of lead pipes, tanks and other lead equipment installed. The dissolution of lead from the yarn prior to the formation of the insoluble lead sulfide has not proven effective or economically sound.

It is, therefore, an object of this invention to provide an improved spinning bath composition which will substantially prevent the formation of dark specks in the finished yarn. Other objects will be apparent from the following description and the appended claims.

The objects of this invention are accomplished by incorporating in any of the usual acid salt spinning baths, used in the viscose rayon process, from 0.01% to 0.1% of the weight of the bath of a salicyl compound of the group consisting of salicylic acid, salicylaldehyde, salicylal ethanolamine, disalicylal ethylene diamine and disalicylal propylene diamine. Less desirable but nevertheless effective compounds which may be used are dimethyl glyoxime, diacetone alcohol, alpha benzoin oxime and ammonium nitroso-B- phenylhydroxylamine (cupferron). Of the compounds listed, those containing at least 20% oxygen are more effective, and those containing aldehyde oxygen are preferred.

The formation of dark specks seems to be definitely tied in with the presence of soluble lead in the bath which precipitates on the gel yarn and is not removed by washing. Presence of lead in this form can be easily determined by analyzing the bath sludge for lead, and it has been shown by numerous tests that the amount of lead in the sludge can be reduced to one tenth or less by the addition of about 0.05% of one of the above listed compounds to the bath. Together with this reduction of lead in the bath sludge, finished yarns substantially free from specks are produced.

The introduction of the compounds abovementioned to the acid salt spinning baths, which may or may not contain zinc sulfate, glucose or other ingredients sometimes used therein, is simply made since all of these compounds except disalicylal ethylene diamine are soluble therein. To incorporate disalicylal ethylene diamine it is first dissolved in dilute aqueous caustic solution, neutralized with sulfuric acid or bath liquor, and then this resulting solution is added to the bath. Spinning of the viscose is conducted in the usual manner and the yarn produced subjected to the customary washing, desulfuring and, if desired, bleaching treatments and dried.

Since many different embodiments of the invention may be made without departing from the spirit and scope thereof, it is to be understood that the invention is not limited by the specific illustrations except to the extent defined in the following claims.

What is claimed is:

1. In the process of spinning viscose rayon into an acid salt bath, the improvement of incorporating solely in the bath from 0.01% to 0.1% of a salicyl compound of the group consisting of salicylic acid, salicylaldehyde, salicylal ethanolamine, disalicylal ethylene diamine and disalicylal propylene diamine the quantities of salicyl compound employed in the process being suitable to avoid the formation of lead specks in the finished yarn Without otherwise changing the properties of the yarn.

2. In the process of spinning viscose rayon into an acid salt bath, the improvement of incorporating solely in the bath from 0.01% to 0.1% of salicylic acid the quantities of salicyl compound employed in the process being suitable to avoid the formation of lead specks in the finished yarn without otherwise changing the properties of the yarn.

3. In the process of spinning viscose rayon into an acid salt bath, the improvement of incorporating solely in the bath from 0.01% to 0.1% of salicylaldehyde the quantities of salicyl compound employed in the process being suitable to avoid the formation of lead specks in the finished yarn without otherwise changing th properties of the yarn.

4. In the process of spinning viscose rayon into an acid salt bath, the improvement of incorporating solely in the bath from 0.01% to 0.1% of salicylalethanolamine the quantities of salicyl compound employed in the process being suitable to avoid the formation of lead specks in the finished yarn without otherwise changing the properties of the yarn.

5. In the process of spinning viscose rayon into assent);

3 an acid salt bath, the improvement of incorporating solely in the bath from 0.01% to 0.1% of disalioylal ethylene diamine the quantities of salieyl compound employed in the process being suitable to avoid the formation of lead specks in the finished yarn without otherwise changing the properties of the yarn.

6. In the process of spinning viscose rayon into an acid salt bath, the improvement of incorporating solely in the bath from 0.01% to 0.1% of disalicylal propylene diamine the quantities of salicyl compound employed in the process being suitable to avoid the formation of lead specks 4 in the finished yarn without otherwise changing the properties of the yarn.

References Cited in the file of this patent UNITED STATES PATENTS Name Date Schuette et al Sept. 13, 1938 OTHER REFERENCES Die Kunstliche Seide, 5th edition Erster Erganzungsband (1931) by Dr. K. Suvern; page 146, paragraph 273.

Number 

1. IN THE PROCESS OF SPINNING VISCOSE RAYON INTO AN ACID SALT BATH, THE IMPROVEMENT OF INCORPORATING SOLELY IN THE BATH FROM 0.01% TO 0.1% OF A SALICYL COMPOUND OF THE GROUP CONSISTING OF SALICYLIC ACID, SALICYLALDEHYDE, SALICYLAL ETHANOLAMINE, DISALICYLAL EHTYLENE DIAMINE AND DISALICYLAL PROPYLENE DIAMINE THE QUANTITIES OF SALICYL COMPOUND EMPLOYED IN THE PROCESS BEING SUITABLE TO AVOID THE FORMATION OF LEAD SPEAKS IN THE FINISHED YARN WITHOUT OTHERWISE CHANGING THE PROPERTIES OF THE YARN. 